Copolymers of acrylonitrile and nicotinamides



Patented Dec. 29, 1953 COPOLYMERS OF ACRYLONITRILE AND -N ICOTINAMIDES George E. Ham and Alfred B. Craig, Decatur, Ala., assignors to The Chemstrand Corporation, Decatur, Ala., a corporation of Delaware No Drawing. Application September 29, 1952,

' Serial No. 312,177

9 Claims. (01. 260-32-6) 1 This invention relates to new and valuable acrylonitrile polymers. More specifically, this invention relates to fiber-forming, acrylonitrile polymers which are dyeable by conventional dyeing procedures utilizing acid dyestuffs. This application is a continuation-in-part of our copending application, Serial No. 206,916,. filed January 19, 1951. I

' It is well-known that polyacrylonitrile and copolymers of acrylonitrile and other polymerizable 1 'mono-olefinic monomers, such as styrene and vinyl acetate are excellent fiber-forming compositions. It is also well-known that the copolymerized monomer may influence the chemical and physical characteristics of the resultant copolymer. Furthermore, it is well-known that polyacrylonitrile and acrylonitrile copolymers may be modified by admixing diiferent polymeric substances.

' Accordingly, the primary purpose of this invention is to provide comonomers which will produce superior fiber-forming polymers having the desirable physical properties of synthetic polyacry- 'lonitrile fibers and at the same time have the desirable chemical properties of natural fibers.

Another object of the invention is to provide different polymeric substances suitable for improving acrylonitrile polymers by blending, especially for the purpose of developing dye ailinity. Other objects and advantages of the present invention will be apparent from the description thereof hereinafter.

In accordance with this invention it has been found that various N-heterocyclic nitrogen compounds containing olefinic functions may be cofpolymerized with acrylonitrile to develop improved dye-receptivity. Suitable N-heterocyclic monomers for copolymerization with acrylonitrile are those having the general formula:

i o-N wherein R is an alkenyl radical selected from the group consisting of allyl, methallyl and ethallyl,

which radical may be attached to either the 2,

N-methallyl-N-methylisonicotinamide, N-allyl- N- methylnicotinamide, N-methallyl-N-ethylnicotinamide, N-allyl-N-propylpicolinamide, etc. The copolymerizable monomers having the above general formula, may be prepared as outlined by Billman and Renclall, J. A. C. S. 66, 540 (1944). In the preparation of copolymers of the above unsaturated cyclic compounds and acrylonitrile it has been found desirable to use from 1 to 15% of the N-heterocyclic compound and to polymerize in the presence of from 85 to 99% of acrylonitrile. It has also been found that the above N-heterocyclic monomers may be introduced into the fiber spinning polymers by a blending technique, and in accordance with this method the N-heterocyclic compound is polymerized by itself or in the presence of other mono-olefinic monomers. For this purpose the other monomers may be vinyl chloride, vinyl acetate, acrylonitrile, styrene, methacrylonitrile, methyl methacrylate, vinylidene chloride, diethyl maleate, dimethyl fumarat, or homologues of these compounds, and

in general, any olefinic monomer which is copolymerizable with the N-heterocyclic monomers. The polymers of the N-heterocyclic compounds for use in the blending procedures will be polymers of 30 to 100% 0f the N-heterocyclic monomers and up to 30% of the other monomer. In

the use of the blending technique it is desirable to use a sufiicient quantity of the blending polymer so as to provide from 1 to 15% of the cyclic monomer in polymerized form in the fiber spinning polymer.

When the blending technique is used in accordance with this invention the principal polymer may be'polyacrylonitrile, or it may be a copoly- 'mer of acrylonitrile with minor proportions of other monomers copolymerizable therewith, for example, vinyl acetate, styrene, methacrylonitrile, vinyl chloride, methyl acrylate, diethyl fumarate,

dimethyl maleate, or homologues thereof. At

least 80% of the acrylonitrile should be used and preferably in excess of 90%. The blends will utilize from 50 to 99% of the principal copolymer and from 1 to 50% of the blending polymer depending upon the amount of N-heterocyclic monomer in the blending polymer.

The blends may be prepared by a wide variety of methods, but for optimum mixing it is desirable to perform the blending when both are dissolved in a common solvent. Suitable solvents for practicing the dispersion will be the same solvents from which the blended polymer is spun into fibers, for example, N,N-dimethylformamide, ethylene carbonate, gamma-butyrolactone, alphahigh molecular weight,

cyanoacetamide, ILN-dimethylacetamide, maleic anhydride, or other solvents known to have the property of dissolving polyacrylonitrile and high acrylonitrile copolymers. The copolymers of acrylonitrile and the above-described N-heterocyclic monomers, the blending polymers of the N-heterocyclic monomers, and the principal polymer with which the blending polymer is mixed may all be prepared by the so-called emulsion or suspension polymerization method in aqueous medium.

a free radical type of catalyst and emulsifying or dispersing agents. The methods. of preparation preferably utilize a mixed monomer addition technique whereby the monomers are mixed in the proportions a and added continuously to the reaction medium throughout the course of the reaction. The various details of the polymerization method should be so selected in order to produce polymers or copolymers of substantially. uniform physical and chemical characteristics. v

The reactions maybe catalyzed with a wide variety of free radical producing substances, for example, the peroxy. compounds, and preferably those which are water-solublafor example, hydrogen peroxide, sodium peroxide, potassium persulfate, calcium percarbonate, and other salts of peroxy acids. In the preparation of some of the copolyme rs of cyclic monomers, the azov catalysts are often found to be effective. Suitable azo catalysts are azo-2,2'-diisobutyronitrile and dimethyl-2,2'- azodiisobutyrate, 2,2-azobis (2,4 dimethylvaleronitrile), and 2,2-azodiisobutyramide. tion, diazoaminoben'zene and its derivatives may be employed as catalysts. The azo catalysts are also found to be desirable in the preparation of the blending polymers, and particularly where a substantial proportion of the polymer is the N-heterocyclic monomer. The principal polymer for blending is preferably prepared in the presence of an alkali metal salt of, peroxysulfuric acid.

The emulsion or dispersing agents used in the practice. of this invention may be any compound which has both a hydrophilic and a hydrophobic radical. Suitable emulsifying or dispersing agents include the common soaps, such as sodium stearate and other alkali metal salts of carboxylic acids and mixtures thereof as obtained by the saponification of animal and vegetable fats, the salts of .sulfonated hydrocarbons, for example, the alkali metal salts of sulfonated paraffins, sulfonatednaphthalenes, and sulfonated alkylbenaenes, the salts of formaldehyde condensed sulfonic acids, and particularly the sodium salt of formaldehyde condensed alkylaryl sulfonic acids, the salts of triethanolamine and other amino soaps, and alkali salts of sulfuric half esters of fatty alcohols.

These polymerizations usually require desired in theultimate copolymer acrylenitrileand the: N-hetero- I In addilecular weight polymer increments and tend to induce a more uniform size of polymer molecules.

The polymerization reactions are preferably initiated by heating a reactor containing water to a temperature under which the polymerization is to be conducted. The aqueous medium is then charged with a catalyst with at least some of the catalyst, dispersing agent, regulator, and redox agent, if they are to be used. The reaction medium is then vigorously agitated by a mechanical stirrer or by tumbling the reactor. When all of the proper conditions for polymerization exist in the reactor, the monomers either pre-mixed or in separate streams are added gradually in. the proportions desired in the copolymer. It is desirable to add the monomers at a rate substantially that in which they are combining in the copolymer. In this manner substantially uniform reaction conditions are maintained in the vessel. Similarly, the catalyst, emulsifying agent, and other reagents are added gradually or intermittently throughout the course of the. reaction so as to maintain preciselyor approximately a uniform concentration of the essential reagents within the reactor at all times. The reaction is then conducted until all. the predetermined lot of monomers is charged. At this point the reaction is terminated. I

In the. practiceof th s invention it is desirable to. maintain substantially uniform reaction conditions. This may be done by adding the monomers at. a fixed constant rate, or by. maintaining the. reaction temperature at a substantially constant level. A pref erred method of conducting the reaction utilizes operation at the reflux temperature, and when this method is used it has been found dasirableto. add the monomers at a varying rate so as to maintain a constant temperture of reflux within the vessel. Operation in this manner will maintain the same quantity and proportion of monomersv in the reaction vessel throughout theentire reaction, but the. proportion of monomers will usually be somewhat different from the proportions which are polymerizing to form the copolymers. Thus, in order to. maintain a. substantially uniform proportion in. the polymer it is desirable to. determine the relationship of the .proportions in the vessel to the proportions in the resulting copolymer. By initially charging the reaction vessel with the proportions of monomers] which are. required in the vessel to form the copolymer of desired proportions, and by adding the monomerthroughout the reaction in the proportions desired in the copolymer and maintaining operation at constant reflux temperature, copolymers very uniform in chemical and physicalproperties will be obtained. It will be apparent. that. since all of the predetermined lot of monomers has been added, the proportion of monomers in the vessel will change due to the depletion of the more active monomer. At thi point it is desirable to interrupt the reaction by removing one of the essential conditions of operation, for example, by lowering the temperature, by destroying the catalystor by rapidly steam distilling. off unreacted monomers,

Upon the completion of the polymerization an emulsion or a suspension of solid polymer in the aqueous medium willbe obtained. Although some of thesev dispersions can be filtered, many are stable emulsions, which must necessarily beprecipitated by the addition of a suitable reagent, for example, aluminum sulfate, sodium chloride, or

another electrolyte, or an alcohol, such as. ethanol,

80 C. for a period of four hours.

0. or by freezing, rapid agitation, or other wellknown means for breaking emulsions.

The solid polymers are substantially free of moisture or can be made so by drying in any conventional oven or by other means known to the art.

The copolymers of acrylonitrile and the heterocyclic nitrogen monomers and the blends of nondyeable acrylonitrile polymers with minor proportions of the polymers or copolymers of the N- heterocyclic monomers, may be spun into fibers or fabricated into films by procedures well-known to the art. The fibers and filmsprepared in this manner will be found to have physical properties greatly superior to all natural fibers and most synthetic fibers, and at the same time have dyereceptivity comparable or superior to natural fibers, such as wool.

Further details of the preparation and use of the new copolymers are set forth with respect to the following specific examples. Unless otherwise specified all parts and percentages are by weight.

EXAMPLE I A glass reaction vessel was charged with 92 parts by weight of acrylonitrile, 8 parts of N- allylnicotinamide, 1.0 part of azo-2,2'-diisobutyronitrile, 0.1 part of the sodium salt of a formaldehyde condensed naphthalenesulfonic acid, and 200 parts of water. The reactor was flushed with nitrogen and sealed with a pressure cap lined with polyethylene. The polymerization was effected by tumbling the reactor in an oven at 75 C. for a period of four hours. The polymer was separated from the aqueous medium by filtration and washed successively with water and alcohol and then dried. Fibers were spun from an 18% N,N-dimethylacetamide solution and stretched 291%. The resulting fiber had a tenacity of 2.3 grams per denier, an elongation of to 6% and a boil shrinkage of 6.2%. The fibers were dyed in a dyebath containing 0.02 gram of Wool Fast Scarlet dye, 0.1 gram sulfuric acid and 41 grams of water for each gram of fiber. The fiber absorbed 76% of the dye in the dyebath in three hours at 100 C. The fibers were dyed to a brilliant scarlet shade. Using a dyebath containing five times the quantity of dye resulted in 27.3% exhaustion and produced a more brilliant shade of scarlet.

EXAMPLE II A mixture of 92 parts of acrylonitrile, 8 parts of N-allylisonicotinamide, 200 parts of distilled water, 1.0 part of potassium persulfate, and 0.1 part of Daxad No. 11 (sodium salt of formaldehyde-naphthalene sulfonic acid condensate) was placed in a pressure bottle. Polymerization was effected by tumbling the reactor in an oven at The copolymer slurry was filtered, washed with water and alcohol, and dried. A 66.4% conversion to a copolymer of specific viscosity in 0.1% dimethylformamide of 0.147 was obtained. A 20% solution of the copolymer in dimethylacetamide was spun through a 30 hole spinneret (each hole 0.005 inch in diameter) into a mixture of 60% dimethylacetamide and 40% water. The fiber was continuously washed, dried on steam-heated rolls, and stretched 248% at 25 lbs. per square inch. The fibers so produced were dyed with dyebath solutions containing 2% and W00 FastScarlet dye and 10% sulfuric acid, said percentages being based on the fiber weight. All the fibers dyed well to medium to dark shades.

EXAMPLE III Using the procedure of Example I a copolymer of 92% acrylonitrile and 8% N-allyl-N-methylnicotinamide was prepared in substantially complete conversion. The copolymer was spun from a solution in dimethylacetamide in the manner described in Example I. Fibers of good dyeability with Wool Fast Scarlet dye were obtained.

EXAMPLE IV at least 2% is a compound having the general formula 0 R M N \R wherein R is an alkenyl radical selected from the group consisting of allyl, methallyl and ethallyl, and R is selected from the group consisting of hydrogen and alkyl groups having from one to 5 carbon atoms.

2. A fiber-forming copolymer of from 90 to 98% by weight of acrylonitrile and from 2 to 10% by weight of a compound having the general formula a A-N \N \R wherein R is an alkenyl radical selected from the group consisting of allyl, methallyl and ethallyl, and R is selected from the group consisting of hydrogen, and alkyl groups having from one to 5 carbon atoms.

3. A fiber-forming copolymer as defined in claim 2 wherein the compound is N-allylnicotinamide.

4. A fiber-forming copolymer as defined in claim 2 wherein the compound is N-allylisonicotinamide.

5. A fiber-forming copolymer as defined in claim 2 wherein the compound is N-allylpicolinamide.

6. A fiber-forming copolymer as defined in claim 2 wherein the compound is N- allyl-N- methylnicotinamide.

7. A fiber-forming copolymer as defined in claim 2 wherein thecompound is N-methallylnicotinamide.

8. A fiber-forming blend of (A) a polymer of a monomeric substance of which acrylonitrile is at least by weight of its polymerizable content and (B) a polymer of at least 30% of a comwherein R. is an alkenyl radical selected from the omens group consisting of oily-1, methallyl and ethallyl, and R is selected irom the group consisting of Hydrogen and 'alkyl groups Having from one to 5 ca b'o'n atoms.

'9. A dyeable fiber foiming composition comprising N,N'-dime chyiia'cetetmide coritainin'g disgsoIve'd therein in polymeric form a; plurality of blefi'nic monomers of which acrylonitrile is at least 80% by weight of the total monomeric tontent, and of which at least' two percent is a com- 1 pound pontaining a heterocyolic nitrogen nucleus and havingth "gfieilal formula 0 one. to '5 carbon atoms.

ii here'in R is an aikenyl radical selected from the grvoup consisting of allyl, methallyl. and ethum, "and R,"- is selected from the group consistof. hydrogen, and. al' 1 groups having from 'GEQRGE E. ALFRED B. No references cited. 

1. A FIBER-FORMING COMPOSITION CONTAINING IN POLYMERRIC FORM A PLURALITY OF OLEFINIC MONOMERS, OF WHICH BY WEIGHT OF THE TOTAL MONOMERIC CONTENT ACRYLONITRILE IS AT LEAST 80%, AND OF WHICH AT LEAST 2% IS A COMPOUND HAVING THE GENERAL FORMULA 